Incandescent electric lamp.



W. R. WHITNEY.

INGANDESCENT ELECTRIC LAMP.

APPLICATION FILED 00131, 1904 W 8 m m n m 7 T W f 2 w LM N H n w E W m W R n I s m h m H W B 9 li vmmw b3 1 E $1 8 y 0 E N Tll W i No. 902,032.

UNITED sT TEs PATENT osnionr TWIIILIS n. WHITNEY, OF'SGHENYEGTA'DY, NEW Yon ASSIGNORITO. GE vERAnELnornrc j .coMPANr, A CORPORATION INCANDESGENT E more especially to the means whereby our? rent may be conveyed into the exhausted chamber containing the incandescing vfila ment. To effect this result I make use of sealing devices in which metal having a dif-' ferent coefficient of expansion from glass is sealed against glass so as to form a tight and permanent joint. The means whereby thisresult is accomplished I have set forth with particularity in the following \d escri tion which is to be taken in connection wit lithe accompanying drawings.

The novel features of my inventionl have pointed out with particularity the append edclaims. s

In thedrawings, Figure 1 is a perspective. view of a lamp embodying my invention, and Fig. 2 a view, partly in section, of thelamp.

In Fig. 1 the usual bulb of an incandescent lamp is indicated at 1. The lower-endof this bulb is open and is of thickened glass as A cap 30f suitable metal, such as copper, brass or iron, is provided withthe "usual external screw-thread 4 by which it may be screwed into the usual receiving socket. This cap is sealed about the lowe'r' end of the portion 2 of the lamp bulb and forms a tight andpermanent joint therewith; j The seal ng operation'is performed by inserting thejglass portion Qinto-the ca 3, withqvhich itmakes a fairly'loose fit, an then carefully heating the parts in the usual glass-blowers gas jets to a temperature suflicient to soften the glass. Air pressure is then applied so as to expand the glass into intimate contact with the metal shell or cap. The parts when cool will be found to make intimate contact with each other and to form a stron and air-tight joint. The metal cap ordinariIy has a higher coefiicient of expansion than the glass so that when the-pa1'ts cool, after having expanded into intimate contact with. eaclrother when heated, the metal contracts t ghtly about the glass. The metal is iuadethm,

. enoughso that I it. will stretch or give lasit comes under tension, and thus prevent .a

Specification of LetterslPatent. Application med October a1 1904. serial No. 230,685.

ever, that numerous.. modificati ons there'off may be made withoutdeparting from. they:

not wishto be lin lite'dthe endof sa1d lamp bulb, the metaljform sealed througha tubular reentra'ntxportion of tube and being under tension.

YoR

" 61 310 LAMP."

fracture of the glass tube. If the metal is too thick the glass will be sheared off,"bu t if thin enough will stretch without injurin "the glass. =A thickness of'metalintheneig borhood of one-hundredth of an inch gives satis factory results. The glass may be of varying thickness but should be sufficient to withstandthe pressure exerted upon it by the.

.metal cap;

The central portion of, the cap 3 I provide with a reentrant tubular member 5. A tube of glass 6=is sealed into the 0 en end of this member 5 in substantially t e manner already described. The inner end of this tube 6 is openbut the outer end is closed by means .of a small cap 7 of a metal such as described. Thiscap is sealed over the end of the glass tube in-the manner before mentioned, and is 3 arranged so that in the com leted article it pro ects somewhat beyondt e level of the #7 5.-

'end 8 of the screw cap ..-.The-filament f the lamp is carried rnetalstandards or wires-1O and 11. These Wire'sareconnected electrically," one,to ,the"'j' cap 3 and the other to the cap 7 ,jand'thus serve, when these. two caps are connected'to' the supply circuit-by screwing the lampinto filament 9'. 1 The lamp whichzIhaveabove'described'lis; 85, intended merely as illustrative of one-of the, variousembodimentsl which; -.=-invemion; may assumeinpractice'i It evidenfihow-B the usual socket, to convey currentto'the spirit of my nvention, for whichreason I-do to the exaetdetails shownanddescribed;

What I claim as new, ddiitd j,

by Letters Patent of the. United States, is

1 Inan vil lcandescent lamp, the-.combii 'a tion of a lam bulb, a'metal cap sealed abo the seal being under tension,' a" glass tube said cap, that ortion of the cap formingthq seal bemg un er tension,' =anda.rnetalcap sealed about the exposed fendflof' -sa-iid l J the "filament; one electrically connectedj to* nth:

the screw ca and the other insulated therefrom by a g ass, tube-tightly clasped under tension by a portion. of said screw cap.

3. In an incandescent lamp, the co1nbinairon of a bulb, a screw cap of 'thin metal ig'htly inclosing the contracted portion of the bulb so as to be under tension, a glass tube tightly inclosed by the screw cap, the latter being under tension, about the tube,

outer 10 tos'etmy 9.04.; 1

In witness" whereof I have hereun hand this-29th day of-October, 1

v ILLIS R. n

Nitnesses:

B XJAMIN B. HULL, HELEN Omono. 

